Fidelity
by Bob The Other Zombie
Summary: It's just past midnight, and Sirius has under twelve hours to figure out why he can't produce a Patronus before his Defense Against the Dark Arts N.E.W.T. tomorrow. Or: Fifteen years before he teaches Harry Potter how to cast a Patronus, Remus has another student.


**A/N: Inspired by JKR saying most Dark Wizards can't cast a Patronus, although I took a few liberties with the rules (no maggots here!). Hope you enjoy!**

* * *

"Come on, Pads, you can do it!" James says.

Sirius bites back a response. It's not James's fault he can't master this bloody spell, but they're at hour three of working on it, and he's getting no closer. Stupid N.E.W.T.s, stupid DADA, stupid Professor MacMillan, stupid Patronus.

" _Expecto Patronum_! _"_ Sirius says again, jabbing at the stone wall across from him as though he's fencing. Predictably, nothing happens.

Peter shifts nervously. "Were...were you thinking of a happy memory?"

"Of course I was bloody thinking of a happy memory, what else would I be doing?" Sirius spits. He wants to snap his wand in half.

The other Marauders exchange worried glances, and James adopts a carefully indifferent tone. "Merlin, MacMillan is so strict. I get that it's wartime and all, but it's such a hard spell, there's no need-"

"There apparently is a need." mutters Sirius. "All of you can do it." That's the worst part of it, if he's being honest. James and Lily, true to their annoyingly married nature, had their gorgeous stag and doe bounding about the room by the end of the second lesson, and spent a good amount of time afterwards kissing in celebration. Peter hadn't kissed anyone, but he'd managed a thick cloud of smoke eventually. And Remus, well...actually, Sirius didn't particularly envy Remus.

"Maybe we should take a break." Remus suggests.

Sirius whirls on him. "We don't have time, Moony, the exam is tomorrow!"

"I think Moony might be right." James says, yawning. "Pads, we've been trying all week, you're frustrated, there's no way you're focusing on happy memories right now. And if we don't get some sleep, you'll be in an even worse mood tomorrow."

"I'll know the spell, though." Sirius pushes his hair out of his face. Unfortunately, there's some truth to James's words. "You're right. Let's go back."

* * *

Once everyone else is asleep, Sirius creeps out of bed. He tiptoes over to James's bed and crouches down, feeling around underneath for the Cloak. When he has it in one hand, he slips out of the door and hurries downstairs.

It isn't until he reaches the dimly lit Common Room that he realizes- the garment he's holding isn't the Cloak. For whatever reason, James has dropped one of his own robes under his bed and never bothered to clean it up. Sirius curses- he doesn't think he'll be able to make a second trip without waking someone up.

"Looking for something?"

Sirius whirls around. Remus stands at the foot of the steps, holding the Cloak in one hand.

"I'm not going to bed." Sirius says. "I've got to learn this."

Remus shrugs. "If that's what you want. But at least let me help."

"You should get to bed." Sirius isn't sure if he wants another person there, especially Remus.

Remus looks back upstairs. "Then I'm taking this back with me. You can wake James if you want it."

"All right, fine." Sirius holds out his hand, and Remus tosses him the Cloak. "Let's go."

* * *

They're silent as they creep through the halls. There isn't quite enough room for both of them under the Cloak, and Sirius is uncomfortably aware of Remus's nearness- his scent, his wiry frame, the softness of his well-worn undershirt. After several tense minutes, they finally reach an empty classroom, and quietly shut the door. Sirius casts _Muffliato_ and a few locking spells on it, too, for good measure.

He examines his wand. "So the thing does work."

Remus dignifies that with a snort as he tosses the Cloak onto one of the desks. "You know how to do it, Padfoot, you're just getting frustrated. It's probably hard to come up with a happy memory when you're picturing Professor MacMillan falling down the stairs."

"Maybe that is my happy thought." mutters Sirius.

Remus raises an eyebrow, but doesn't respond. "What do you think your happiest memory is?" he asks instead.

Sirius fiddles with his wand. "I dunno, it's hard to choose." It's not that he doesn't have happy memories. He does, plenty of them, all of the pranks and dates and laughter he's experienced at Hogwarts, but none of them have been enough. "Which one do you use?"

Remus fidgets, sitting down on a desk. "You guys, mostly. That first prank we pulled together, first year, remember?"

Sirius remembers. It was late in first year, the first time they'd all properly worked together. Their target had been a few fourth-year Gryffindors. Their idea was slipping Chocolate Frogs into the fourth year's schoolbags right before class, so the frogs would croak and disturb everyone. And then Sirius, giddy with this initial success, had escalated- they'd snuck into their adversaries' bedroom and slipped a few more Frogs into the boys' beds.

"The Chocolate Frogs?" Sirius chuckles. "What amateurs we were, Moony. Look at how much we've grown since then."

Remus looks down at his hands in his lap. "More- afterwards. After we got caught, and they chased us out of Gryffindor Tower, and we ended up lost in the hallways after curfew."

"And then James showed us the Cloak and we all lost our minds. And then we somehow managed to find our way back without running into Filch." says Sirius. "Yeah, I remember. Is that really your happiest memory?"

Remus shrugs. "It was the first time we were really a group, you know? Felt nice."

Sirius nods. "Fair enough. I'll try it." The memory, if anything, has calmed him down a bit. He squeezes his eyes shut, focusing on the breathless excitement and newfound camaraderie, and tries to let the feeling fill him from his toes to the tip of his skull. " _Expecto Patronum!"_

He doesn't need to open his eyes to see that nothing has happened. His wand still feels cold. "Well, maybe that's not it."

Remus stands, pulling out his wand. "Look, maybe you've got the movement wrong. You're supposed to do kind of a circular motion." He demonstrates.

Sirius imitates him. It doesn't feel any different. "That's what I've been doing this whole time!"

"No, you're still doing more of a stabbing thing." Remus says. "Here. _Expecto Patronum._ " Slowly, Remus goes through the motion, and his Patronus appears for an instant before he sends it away with a flick of his wand. Sirius blinks at the empty space and then at Remus.

"Moony-"

Remus shakes his head. "Just try it."

Sirius obediently closes his eyes again, searching for another happy memory. Maybe...yeah, his first Christmas with the Potters. That'd been a good one. Mrs. Potter had cooked more food than anyone had known what to do with, and after opening presents, he and James had barely been able to leave their beds for the rest of the day. It had amazed him how simple it all was, without guilt, or fighting, or tears. He'd never felt such utter satisfaction.

" _Expecto Patronum!"_

Sirius lets out a frustrated groan when he opens his eyes to yet another failure. "All right, what were you saying about my movement?"

"You need to- erm- here." Remus crosses to him and lightly takes his wrists. Sirius's eyes flick nervously up to Remus's face, his stomach fluttering. "Try going up a bit more, like this. Expecto...Patronum." Remus meets his eyes, and his grip on Sirius's wrists slackens.

Before Remus can pull away, Sirius moves his hands in the pattern Remus has shown him. "Expecto Patronum. Like that?" The thought pops into his head that he could do it incorrectly, get Remus to keep touching him, accompany it with his usual cocky smirk. Sirius ignores it.

"Yeah, better." Remus takes a step back, biting his lip. "All right, try it like that."

Sirius closes his eyes again, pulse still racing. For some reason, he can't quite concentrate.

"Sirius?"

"Sorry, just trying to come up with a good one." Sirius says. In his distracted state, the only happy memory he can think of is one afternoon fifth year, when he and Remus were alone in the Common Room. Remus was studying for the O.W.L.s, while Sirius lay back on the couch, feet resting up against Remus's lap. Soon after, Sirius would get bored and start contemplating the ways he could break Remus's focus, but at that moment, all he had felt was content at having a lazy afternoon with a close friend.

Sirius makes sure to move his wand in a circle this time. " _Expecto Patronum!"_

He feels warmth and opens his eyes. Thin, white mist trails from his wand, sparks dancing around it.

Remus's mouth has dropped open. "You did it! It was incorporeal, but-"

Sirius, however, makes a frustrated noise in the back of his throat. "It was kind of thin, wasn't it? Pete's incorporeal was a lot bigger."

"Well, maybe it was the happy memory, then." Remus says, leaning on the desk behind him. "Which one did you use?"

"Uh...first kiss." says Sirius. "But yeah, maybe I'll try a happier one." He closes his eyes, not wanting to think about why he'd lied, and pictures the happiest day of his life- the day he'd moved in with the Potters. They'd picked him up at the Hogwarts Express, in the pouring rain he might add, and even though James had made the offer ahead of time, Sirius hadn't quite believed it until the Potters had given him a hug and helped him unload his trunk. Like he was their son. " _Expecto Patronum!"_

His wand emits sparks, but there's no white smoke. For a moment, Sirius can't believe it, and then he meets Remus's disappointed gaze. Sirius growls in frustration. "Fuck! This bloody spell is toying with me!"

"What were you-"

"Moving in with Prongs, what could be happier than that?" Sirius snaps, and immediately regrets it when Remus folds his arms, looking away.

"Sorry, Moony." Sirius shakes his head. "Maybe I'm not supposed to be able to cast this."

Remus's gaze is on him immediately, sharper than a dragon's tooth. "What do you mean by that?"

Sirius ducks his head. "Nothing. Forget it." He can still feel Remus examining him, and his neck suddenly itches. "Do you think maybe it's because there's no Dementors around? Maybe I need urgency to cast it."

Remus accepts the subject change with a quirk of his lips. "I don't know how we could solve that. What, do you want to take a quick trip to Azkaban?"

"You think that'd get me some extra credit with MacMillan?" Sirius says.

Remus snorts. "Unless you somehow kidnapped a Dementor and brought it in for the exam-"

"You could dress up as one." Sirius says. "You've got a cloak, just pull it over your head and make some hissing noises." Sirius raises his arms and adopts a slack-jawed expression.

"What are you, an Inferi?"

Sirius walks towards him slowly, arms outstretched. "Ooooh, Moooooony, I want to eat your sooooul, ooooh, Moooony-"

Remus shoves him away, but he's laughing. "Sirius, stop."

"What, you don't want a kiss?" Sirius says. In the brief silence afterwards, Sirius registers two things- one, he actually did just say that. And two, Remus is bright red.

The impulsive part of him wants to pursue it further, and he almost does. Except the majority of him recognizes a terrible idea when he sees it. Sirius backs away, hopping up onto a desk. "I don't think I'd make a very good Dementor."

"I don't think so either." Remus says, staring at the wall behind Sirius. "I don't think Dementors can talk."

Sirius laughs loudly, too loudly, and Remus looks back at him with raised eyebrows. "Sirius, what did you mean about you're not supposed to cast it?"

Immediately, the mirth drains out of Sirius. "I said forget it."

"Pads-"

Sirius crosses his arms. "Look, maybe my happy memories aren't all that happy right now." It's the partial truth, anyways. "Because they're all from Hogwarts, and now we're graduating."

Remus mirrors his position, wrapping his arms around himself."We'll be fine. We'll all take care of each other, and the Order-"

"I know." Sirius snaps. He wishes Remus would respect the taboo of the future, the way James and Peter do. He wishes Remus couldn't tell how worried he was, or that he didn't know how worried Remus was. "Merlin, I don't know how you cast _Expecto Patronum_ either, honestly."

Sirius regrets saying it at once when Remus's hands tighten on his forearms. "Carefully." His tone is detached.

"Moony, I didn't mean that, and your Patronus-"

Remus, however, is shaking his head, clearly done with the subject. "What did you mean by you aren't supposed to cast it?"

"Moony, I said forget it." Sirius slides off of his desk and paces impatiently to the front of the room.

"Do you think maybe you're having trouble because you don't think you can do it?"

"No." Sirius scoffs, sitting on the professor's desk. "I think if I were able to do it, I'd be able to do it!"

Remus's gaze is burning a hole into him. "Why do you think you can't cast a Patronus, Sirius?"

Sirius gestures at the Patronus-less room around him, and Remus raises an eyebrow, as if to say, _You know what I mean._ Finally, Sirius sighs. "I'm a Black, Remus. In the grand spectrum of magic, we aren't exactly on the Light side. Not many Dark Wizards can cast a corporeal Patronus."

Unbelievably, Remus snorts, and Sirius stiffens. "Is something funny?"

Remus shakes his head. "You do realize I'm a werewolf, right?"

"Yeah, but- you're not a Dark Wizard!" Sirius says. "You're about as Light as it gets, twenty-nine days out of the month."

Remus scoffs. "Pretty sure the Dark creature bit outweighs all of that. If I can do it, you can do it."

"Clearly, I can't." mutters Sirius. "And you're not a creature."

Something shifts in Remus's gaze, and he stands, facing Sirius, arms still folded. "Sirius, you want to know what my happiest memory is?"

"The whole first prank thing?"

"Not just that." Remus says. "It's you. After we got back, I figured that was the end of us being friends, so I left you three to go change out of my robes. You followed me, and said 'That wasn't so bad, was it?' and started laughing like a lunatic, and didn't mention the scars on my chest, and I realized I might actually be able to have normal friends despite my furry little problem. "

Sirius's throat is suddenly dry. He clears it. "C'mon, I was curious. I thought you were as straight-laced as they come, and then you crawled under the Gryffindor table to get the frogs into their bags."

Remus smiles slightly. "Sirius, you're not a Dark Wizard. For Merlin's sake, the Order themselves started recruiting you almost the moment you turned 17. Your best friends are a halfbreed, a halfblood, and the world's biggest Muggle lover dating a Muggleborn, and you risk your life for them regularly. You haven't even lived at home for two years. Who cares who your family is? You're Light, through and through."

For a moment, Sirius can't look away from the intensity of Remus's gaze, and then Remus looks down at his feet. "Try again, Pads."

Sirius stands, trying to come up with a happy memory, but his mind is too full of Remus's words. He moves his wand anyways. " _Expecto Patronum!_ "

Much to his surprise, white smoke pours out of his wand. Sirius gapes.

"You did it!" Remus says. "That's an incorporeal, you did it! What were you thinking about?"

"I- uh-" Sirius runs a hand through his hair. "Merlin, Moony, that was one hell of a pep talk." He meets Remus's eyes, and Remus reddens again.

"Well." Remus stands, picking the Cloak up off of the desk. "You wanna go back now? That should be enough for tomorrow-"

Sirius focuses again, moving his wand like Remus has shown him, concentrating on Remus's words. " _Expecto Patronum!"_ The white vapour appears again, drifting through the air. "Moony, you should be a professor. I mean, I know you want to be a professor, but you really should."

Remus stops by the door, one hand on the doorknob. "Thanks."

"No, thank you." Sirius says, smiling at him. Merlin, sometimes he loves this boy. He really, really does.

"We should probably get going if we want to get back without getting caught." Remus says, looking at the door. "Or if we don't want Prongs and Wormtail wondering where we are-"

Sirius slumps against the professor's desk. "I don't feel like going back, do you? It's past two in the morning, I'm too tired to sneak around." And it's true enough- now that the excitement of his Patronus has faded, he's beginning to feel the strain of the past several hours.

Remus lets go of the doorknob and crosses back towards him. "We could always try and sleep here. I don't feel much like sneaking back, either."

Sirius fakes a gasp, even as he slouches onto the floor. "What, are you suggesting we stay out all night? Why, Moony, I'm shocked, how dare you besmirch the honor of the Prefects-"

Remus, despite the pensiveness in his face, smiles as he sits down next to him. "Not a Prefect anymore. Not after this week."

"Once a Prefect, always a Prefect." mutters Sirius, trying to get comfortable. "You'll be a Prefect til the day you die. C'mon, gimme the Cloak, we can use it as a pillow."

Remus lies down beside Sirius as Sirius spreads out the Cloak enough to cushion both of their heads. It's not particularly cozy on the floor, but there's something comforting about Remus's warmth beside him, his little noises as he gets settled. As Sirius begins drifting off into sleep, words float through his mind, a thought from earlier resurfacing.

He loves this boy. _Loves_ this boy.

Oh.

Sirius opens his eyes to find Remus watching him with such affection that it takes Sirius's breath away. Remus looks away almost immediately, and Sirius lifts himself up onto one elbow.

"Go to sleep, Pads." says Remus.

Sirius slowly leans forward, pressing a tiny kiss to Remus's shoulder. This time, when Remus looks at him, he doesn't look away. Sirius inches closer, stopping with his lips almost touching Remus's, waiting for some kind of sign that this isn't all in his head.

Remus kisses Sirius. It's a gentle, cautious kiss, and then Sirius grips Remus's shoulder tightly, pulling him closer. For a long moment, Sirius loses himself entirely in Remus's warmth and the slow soft sweetness of the kiss, and then his arm, half-pinned under his body weight, protests loudly, and Sirius pulls away to readjust. When he turns back to Remus, Remus has shifted backwards slightly, face pensive again.

"We should really get to sleep." Remus whispers.

Sirius is too tired to argue, so he rolls onto his stomach, letting his arm rest against Remus's side. When he cracks open his eyes a moment later, Remus is staring at the ceiling, one thumb absentmindedly rubbing his lips.

* * *

The next morning, the stiffness wakes him up as the sun is rising. His back, shoulders, and neck have not appreciated the night on the hard floor, and it takes Sirius a moment to register the rest of his surroundings- the soft Cloak beneath his head, the grayish morning light streaming in through the classroom windows, and the warm body beside him, that he's inexplicably thrown his arm around and tangled a leg through in the night.

Remus has fallen asleep facing him, one hand resting in between their noses. In the stark morning light, with hair tousled by sleep and deep lines on his face from the Cloak and a shiny trail of drool coming out of his mouth, he is, strangely, beautiful. The events of last night flicker through Sirius's mind- Remus, encouraging him, comforting him, laughing with him, talking sense into him, watching him, correcting his movements with that odd intense look in his eyes. Sneaking out with him even though it was past midnight, just so Sirius would have company. Turning red and kissing him, so gently that Sirius is still half-convinced it was a dream. And that thought he couldn't shake, no matter how much it might complicate things. He loves Remus, and not just as a close friend.

Sirius groans, gently extracting himself from Remus. He picks up his wand from the floor, and thinks about how, growing up a rebellious child in a loveless family, he'd never imagined finding someone like Remus. " _Expecto Patronum!"_

The sudden warmth almost makes him drop his wand. A large dog bursts out of the tip and gallops around the room, tongue wagging out of its mouth with all the joy Sirius feels at that moment. "Yes!" Sirius shouts, and then claps a hand over his mouth, looking back down at Remus.

Remus shifts, turning onto his back. "Sirius?" he mutters, rubbing at his eyes. "What time is it?"

"I dunno. Moony, cast your Patronus."

Remus sits up, squinting at him. "What? Why?"

"Cast your Patronus." Sirius says. "C'mon, trust me, just do it."

Remus picks up his wand. " _Expecto Patronum!"_ The wolf erupts out of it. It's better behaved than Sirius's dog, pacing back and forth in front of its master.

Before Remus can dismiss it, Sirius grabs his arm. "Hold on. _Expecto Patronum!"_ His dog emerges again, and joyfully runs up to the wolf. The wolf snaps at it playfully, and the two canines chase each other around the room.

Remus gapes. "But- when?"

"Just before you woke up." Sirius says, grinning at him. "While I was remembering how much you did for me last night." He moves closer, still holding onto Remus's arm. "Dog and wolf. It's not a stag and a doe, but it's something, innit?"

Remus looks at him for a moment. "So you figured me out." he says drily. "I was wondering when you'd notice. Pretty sure Prongs has known since fifth year."

"Nah, I figured me out." Sirius says, leaning in until they were nose-to-nose. "You gave yourself away with the whole kissing thing."

Remus smirks. "What, when you tried to snog my shoulder?"

In response, Sirius kisses Remus, clambering over him until he's kneeling practically in Remus's lap. Their Patronuses disappear unnoticed as Remus pulls Sirius closer to him. Sirius decides he could stay like this forever, running his fingers through Remus's bedhead, with Remus's arms around him and Remus's lips on his and Remus's legs intertwined in his own. When they break apart, Remus is breathing heavily, and Sirius finds an immense satisfaction in coaxing that reaction out of him.

"We should get back." Remus whispers. "Prongs and Wormtail will wonder where we are."

"Fuck them." says Sirius, kissing Remus again, one hand stroking his chest.

It takes Remus a moment to pull away. "And other people need to use this classroom."

"Fuck them, too." Sirius says, leaning forward, but Remus stops him with a hand on his shoulder.

"And we've got the exam." Remus says. "You don't want all this work to be wasted, do you?"

Sirius smirks at him, his usual cocky smirk. "Hasn't been wasted from where I'm sitting."

Remus rolls his eyes, smiling. "How about we come back here tonight, then. As a reward for the exam."

"I can live with that."

They kiss once more before Sirius stands, reaching down a hand to help Remus up. When Remus follows him, neither boy drops their hand, and as they undo the spells on the door, Sirius knows without a doubt he'll pass his DADA exam this afternoon.

He's already got the perfect happy memory in mind.


End file.
